Switchgear with panels overlying access openings interlocked with grounding switches by means of j-shaped latches



3,459;905 RLYING ACCESS OPENINGS INTERLOCKED 6 Sheets-Sheet 1 J. JEFFRIES WITH GROUNDING SWITCHES BY MEANS OF J-SHAPED LATCHES Filed July 15, 1967 Aug. 5, 1969 SWITCHGEAR WITH PANELS ov Aug. 5, 1969 J JEFFRIES 3,459,905

SWITCHGEAR WITH PANELS OVERLYING ACCESS OPENINGS INTERLOCKED WITH GROUNDING SWITCHES m' MEANS OF J-SHAPED LATCHES Filed July 15, 1967 5 Sheets-Sheet %b Wm New; m6 8 Aug. 5, 1969 J.E.JEFFR|ES 3,459,905

SWITCHGEAR ,WITH PANELS OVERLYING ACCESS OPENINGS INTERLQCKED WITH GROUNDING SWITCHES BY MFIANS OP -l--SHAPED LATCHES Filed July 15, 1967 5 SheetsSheet 3 Aug. 5, 1969 J. E JEFFRIES SWITCHGEAR WITH PANELS OVERLYING ACCESS OPENINGS INTERLOCKED WITH GROUNDING SWITCHES BY MEANS OF J-SHAPED LATCHES Filed July 13, 1967 5 Sheets-Sheet 4 Aug. 5, 1969 J. E. JEFFRIES 3,459,905

SWITCHGEAR WITH PANELS OVERLYING ACCESS OPENINGS INTERLOCKED WITH GROUNDING SWITCHES BY MEANS OF J-SHAPED LATCHES Filed July 13,- 1967 s Sheets-Sheet 5 United States Patent US. Cl. 200-50 6 Claims ABSTRACT OF THE DISCLOSURE The panels overlying access openings to energizable parts of metal enclosed switchgear are interlocked with grounding switches.

This invention relates to safety arrangements for metal enclosed switchgear with grounding switches and constitutes an improvement over the switchgear of application Ser. No. 585,610, filed Oct. 10, 1966, Patent No. 3,339,118, issued Aug. 29, 1967.

The switchgear disclosed in the above patent is particularly adapted for use in high rise buildings and the like and for operation by relatively unskilled personnel. Circuit controlling and protecting switches and fuses are mounted in a metal enclosure and grounding switches are arranged to connect energizable parts to ground to protect a person undertaking to service these parts.

Among the objects of this invention are: To prevent access to the normally energized parts unless they are connected to ground by closure of the grounding switch or switches; to provide one or more removable panels or closures over access openings in a wall of the metal enclosure which permit entrance to the enclosed energizable parts and to interlock the panels or closures with one or more grounding switches to prevent removal of the panels or closures unless the associated grounding switches are closed; and to operate the interlock mechanism conjointly with rotation of a shaft that rotates the ground switch blades.

According to this invention an array of energizable contacts of metal enclosed switchgear can be serviced through an adjacent opening in the wall of the housing. A removable access panel or closure normally overlies the opening to prevent unauthorized entrance. Ground switch blades, one for each phase, are rotatable on a common shaft to engage the contacts. A latch within the housing is arranged to be operated by the shaft to unlatch the associated access panel or closure only when the contacts are connected to ground by the ground switch blades.

In the drawings: FIGS. 1A and 1B, the former being placed above the latter, show a vertical sectional view of metal enclosed switchgear, the switchgear being shown principally in elevation. FIG. 2 is a vertical sectional view taken generally along the line 22 of FIGS. lA-lB. FIG. 3 is a vertical sectional view, at an enlarged scale, taken generally along the line 33 of FIG. 2. FIG. 4 is a horizontal sectional view taken generally along the line 44 of FIG. 2 and shows the access panel or closure in the closed position. FIG. 5 is a view, similar to FIG. 4, and shows the manner in which the access panel or closure is applied or removed. FIG. 6 is a view, in rear elevation, of the switchgear shown in FIGS. lA-lB, the upper access panel or closure having been removed. FIG. 7 is a vertical sectional view taken generally along the line 77 of FIG. 6.

In FIGS. 1A-1B, 2 and 6 the reference character 10 designates, generally, a metallic housing containing switchgear to be described. The metallic housing 10 has left 3,459,905 Patented Aug. 5, 1969 ice and right side walls 11 and 12, front and rear walls 13 and 14, and top and bottom walls 15 and 16. Windows 17 and 18 are provided in the left side wall 11, and simi lar windows (not shown) are provided in the right side wall 12 to permit visual inspection of the interior of the metallic housing and particularly of the switchgear mounted therein. Suitably mounted between the side walls 11 and 12 are upper and lower transverse channels 19 and 20 that are arranged to carry upper and lower insulators 21 and 22. For a three phase installation, as shown in FIG. 6, there are three upper insulators 21. A like number of lower insulators are also employed. For single phase operation it will be understood that only single upper and lower insulators 21 and '22 are employed. Under certain circumstances only the upper insulator 21 may be used with the accompanying switchgear. However, for illustrative purposes the polyphase arrangement with upper and lower switchgear sections is disclosed.

The upper and lower insulators 21 and 22 are arranged to carry upper and lower feeder contacts that are indicated, generally, at 23 and 24 and to which upper and lower feeder conductors 25 and 26 are connected for energization from a suitable remote source. Upper and lower feeder switch blades 27 and 28 are arranged to have contact engagement with the upper and lower feeder contacts 23 and 24. Upper and lower feeder switch blade operating assemblies, shown generally at 29 and 30, are suitably mounted within the metallic housing for rotating the feeder switch blades 27 and 28 between the circuit closed position shown in FIG. 1A to the circuit open position shown in FIG. 1B and vice versa. Manually operable upper and lower handles 31 and 32 are arranged to effect movement of the feeder switch blades 27 and 28 by way of the feeder switch blade operating assemblies 29 and 30. The feeder switch blades 27 and 28 are mounted on upper and lower switch blade support plates 33 and 34 which are arranged to be rotated by the operating assemblies 29 and 30 under the control of the manually operable handles 31 and 32. Common connections 35 between the switch blade support plates 33 and 34 serve to connect them to one end of fuses, one of which is shown at 36. It will be understood, that, for three phase operation, three fuses 36 are employed. At their other ends load contacts, one shown at 37, are provided for connection to the fuses 36. The load contacts 37 are mounted on insulators 38 of which there are three as shown in FIG. 2 for polyphase operation. The insulators 38 are mounted on a transverse channel 39 that is suitably mounted within the metallic housing 10 adjacent the rear wall 14 thereof. Load conductors, one of which is shown at 40, are provided for connecting the load contacts 37 to a load.

It will be understood that the arrangement is such that the load conductors 40 can be energized through the fuses 36 either from the upper feeder conductors 25 or the lower feeder conductors 26, depending upon the positions of the feeder switch blades 27 and 28. Also it is possible to transfer the connection to the load conductors 40 from the feeder conductors 25 to the feeder conductors 26 without interrupting the energization of the load conductors 40.

Under certain circumstances it is necessary to service the upper and lower feeder contacts 23 and 24 and to do this they should be deenergized and remain deenergized during the servicing period. This is accomplished by deenergizing the upper or lower feeder conductors 25 and 26 by other means (not shown). While one set of feeder contacts, for example the feeder contacts 23, is being serviced, it is desirable to maintain energization of the load conductors 40 from the other feeder contacts 24.

In order to make certain that the feeder contacts 23 and 24 remain deenergized while they are being serviced,

they are provided with upper and lower ground contacts 43 and 44 that are arranged to be engaged, respectively, by upper and lower pairs of ground switch blades 45 and 46 while are shown more clearly in FIGS. 1A-1B, 2 and 3. The pairs of ground switch blades 45 and 46 are commonly mounted on upper and lower ground switch shafts 47 and 48 that are suitably journaled at their ends within the metallic housing 10. Hexagonal ends 49 and 50 are provided for the upper and lower ground switch shafts 47 and 48 to receive at either end a wretch for rotating them and therewith the ground switch blades 45 and 46 into engagement with the upper and lower ground contacts 43 and 44. Flexible ground conductors 51 and 52, FIG. 2, are provided for interconnecting the upper and lower ground switch shafts 47 and 48 to the rear wall 14 of the metallic housing 10.

In order to prevent closure of the ground switch blades 45 and 46 when the respective feeder switch blades 27 and 28 are closed, upper and lower locking cams 55 and 56 are mounted on the ground switch shafts 47 and 48- for rotation therewith. The locking cams 55 and 56 include upper and lower arms 57 and 58 and are provided witth arcuate slots 59 and 60 that are arranged to register with pins 61 and 62, as shown in FIGS. 1A and IE, to permit operation of the respective ground switch blades 45 or 46 when the corresponding feeder switch blades 27 or 28 are open. The pins 61 and 62 are carried by upper and lower locking arms or links 63 and 64 with the pins 61 and 62 being guided in slots 65 and 66 in; upper and lower channel shaped brackets 67 and 68 which are secured to the left side wall 11. At their other ends the locking arms or links 63 and 64 are pivotally connected at 69 and 70 to upper and lower locking levers 71 and 72 which are arranged to rotate witth the feeder switch blades 27 and 28. When the upper feeder switch blades 27 are closed, as shown in FIG. 1A, the pin 61 underlies the upper arm 57 of the cam 55 and prevents rotation of the upper ground switch blades 45 into contact engagement with the upper ground contacts 43. When the lower feeder switch blades 28 are open, as shown in FIG. 1B, the pin 62 registers with the arcuate slot 60 and permits rotation of the lower ground switch blades 46 into contact engagement with the lower ground contacts 44. Of course this assumes that the lower feeder conductors 26 have been deenergized.

Servicing of the upper and lower feeder contacts 23 and 24 and the parts associated therewith is facilitated by the provision of access openings 77 and 78, FIG. 2, in the rear wall 14. These openings are defined on three sides by inwardly offset border flanges 79 and 80 that are arranged to receive upper and lower removable access panels or closures 81 and 82. The upper and lower access panels or closures 81 and 82 are arranged to be secured in position by screws 83 as shown in FIG. 6 for the rear access panel or closure 82. An intermediate panel 84 is secured in place such that it cannot be removed from the exterior of the metallic housing 10.

In accordance with this invention provision is made for interlocking the upper and lower removable access panels or closures 81 and 82 with the respective ground switch blades 45 and 46 so as to prevent removal of the access panels or closures 81 and 82 unless the ground switch blades 45 and 46 have been operated to engage, respectively, the upper and lower ground contacts 43 and 44. For this purpose upper and lower interlocking means shown, generally, at 89 and 90 are provided. The interlocking means 89 and 90 include upper and lower I-shaped members that are indicated, generally, at 91 and 92. They include relatively long arms 93 and 94, respectively, that are slidably mounted in loops 95 which are suitably secured, as by welding, to the inner surface of the rear wall 14. The J-shaped latch members 91 and 92 also include short arms 97 and 98 that are arranged to slide into and out of loops 99 and 100 that are suitably secured, as by welding, to the inner surfaces of the upper and lower removable access panels or closures 81 and 82.

The loops 99 and extend through notches 101 and 102 in the adjacent offset border flanges 79 and 80 and thus serve to cooperate with the edges thereof for locating the removable access panels or closures 81 and 82 in proper registry with the upper and lower access openings 77 and 78. Slots 103 and 104 are provided in the offset ends 105 and 106 of the long arms 93 and 94 for receiving pins 107 and 108 that extend radially from collars 109 and 110 that are secured to and rotate respectively with the upper and lower ground switch shafts 47 and 48.

:When the upper ground switch blades 45 are rotated into engagement with the upper ground contacts 43, as shown in FIG. 3, the radial pin 107 extending through the slot 183 moves the J-shaped latch member 91 upwardly and withdraws the short arm 97 thereof from the loop 99. This then permits the upper removable access panel or closure to be swung away from the border flange 79 as shown in FIG. 5.

Since it is desirable that any removal of the access panels or closures 81 and 82 be prevented after only the screws 83 are removed and before the ground switch blades 45 and 46 are closed hooks 111 and 112 are welded to the border flanges 79 and 80 as shown in FIG. 2. The hooks 111 and 112 have offset bifurcated ends 113 and 114 which, as shown in FIG. 4, are arranged to overlie the inner surfaces of the adjacent border flanges 79 and 80 with the furcations being located on opposite sides of inwardly extending pins 115 and 116. As shown in FIG. 5, when the upper removable access panel or closure 81 is moved into closing position, the furcations of the bifurcated end 113 are positioned on opposite sides of the inwardly extending pin 115 and the access panel or closure 81 then is swung to the closed position where the loop 99 projects through the notch 101 in position to receive the short arm 97 of the J-shaped latch member 91.

As shown in FIG. 7 the joints between the upper and lower removable access panels or closures 81 and 82 and the adjacent edges of the intermediate panel 84 are closed by transverse angle members 117 and 118. The angle members 117 and 118 prevent insertion through the respective joints of relatively thin objects which might be employed in an attempt to poke something of a foreign nature into the interior of the metallic housing 10 where it might come in contact with an energized part, such as the feeder contacts 23 and 24.

What is claimed as new is:

1. Switchgear comprising:

a metallic housing,

a feeder contact insulatingly mounted in said housing for connection to a high voltage source,

a ground switch blade in said housing connected thereto for engaging said feeder contact,

said metallic housing including a wall having an opening adjacent said feeder contact permitting access thereto, a removable closure for said opening, and interlocking means in said housing connected between said ground switch blade and said closure to permit removal of said closure from said access opening only when said ground switch blade engages said feeder contact, said closure overlying said wall and having a locking portion projecting therethrough into said housing,

said interlocking means including latch means movably mounted inside said housing for engagement with said locking portion of said closure, and

connecting means between said latch means and said ground switch blade for moving said latch means into or out of locking engagement with said locking portion,

said latch means being a J-shaped member with the distal end of its short arm movable into and out of said locking engagement and its long arm slidably mounted on the inside of said wall with the distal end thereof operatively connected to said ground switch blade.

2. Switchgear comprising:

a metallic housing,

a feeder contact insulatingly mounted in said housing for connection to a high voltage source,

a ground switch blade in said housing connected thereto for engaging said feeder contact,

said metallic housing including a wall having an opening adjacent said feeder contact permitting access thereto,

a removable closure for said opening, and

interlocking means in said housing connected between said ground switch blade and said closure to permit removal of said closure from said access opening only when said ground switch blade engages said feeder contact,

said closure overlying said wall and having a locking portion projecting therethrough into said housing,

said interlocking means including latch means movably mounted inside said housing for engagement with said locking portion of said closure,

connecting means between said latch means and said ground switch blade for moving said latch means into or out of locking engagement with said locking portion,

said locking portion being carried by said closure along one side thereof, and

a hook carried by said closure along the side thereof opposite said one side and extending through said access opening with its distal end overlying the inside of said wall.

3. Switchgear according to claim 2 wherein:

said distal end of said hook is bifurcated, and

a pin extends from said wall between the furcations of said distal end of said hook.

4. Switchgear comprising:

a metallic housing,

a feeder contact insulatingly mounted in said housing for connection to a high voltage source,

a ground switch blade in said housing connected thereto for engaging said feeder contact,

said metallic housing including a wall having an opening adjacent said feeder contact permitting access thereto,

a removable closure for said opening,

interlocking means in said housing connected between said ground switch blade and said closure to permit removal of said closure from said access opening only when said ground switch blade engages said feeder contact,

a shaft rotatably mounted in said housing and having said switch blade secured thereto,

said closure overlying said wall and having a locking loop projecting therethrough into said housing, and

said interlocking means including a J-shaped member the distal end of the short arm of which is movable into and out of locking engagement with said locking loop and the long arm of which is slidably mounted on the inside of said wall, and

an operating member extending from said shaft and engaging the distal end of said long arm for moving said J-shaped member on rotation of said shaft to move said distal end of said short arm into and out of locking engagement with said locking loop.

5. Switchgear according to claim 4 wherein:

said locking loop is carried by said closure along one side thereof, and

a hookis carried by said closure along the side thereof opposite said one side and extends through said access opening with its distal end overlying the inside of said wall.

6. Switchgear according to claim 5 wherein:

said distal end of said hook is bifurcated, and

a pin extends from said Wall between the furcations of said distal end of said hook.

References Cited UNITED STATES PATENTS 3,385,938 5/1968 Schockelt ZOO-50.1

FOREIGN PATENTS 749,484 5/ 6 Great Britain. 1,150,743 6/ 1963 Germany.

ROBERT K. SCHAEFER, Primary Examiner R. A. VANDERHYE, Assistant Examiner 

